test: add unit tests for retryWithBackoff

Author: sapnilbiswas

js/__tests__/retryWithBackoff.test.js

@@ -154,19 +154,24 @@ describe("retryWithBackoff", () => {
     describe("max retries exceeded", () => {
         it("should reject with an error when max retries are exhausted", async () => {
             const check = jest.fn(() => null);
+            const onRetry = jest.fn();
+            const delayFn = jest.fn(() => Promise.resolve());
 
             await expect(
                 retryWithBackoff({
                     check,
                     onSuccess: jest.fn(),
-                    delayFn: instantDelay,
+                    onRetry,
+                    delayFn,
                     maxRetries: 3,
                     errorMessage: "COULD NOT CREATE CACHE"
                 })
             ).rejects.toThrow("COULD NOT CREATE CACHE");
 
             // check called for attempts 0, 1, 2, 3 then fail on count=4 > maxRetries=3
             expect(check).toHaveBeenCalledTimes(4);
+            expect(onRetry).toHaveBeenCalledTimes(3);
+            expect(delayFn).toHaveBeenCalledTimes(3);
         });
 
         it("should use default error message when none provided", async () => {
@@ -226,6 +231,25 @@ describe("retryWithBackoff", () => {
             // First delay should be 50 * 2^0 = 50
             expect(delayFn).toHaveBeenCalledWith(50);
         });
+
+        it("should use default delay function if none provided", async () => {
+            jest.useFakeTimers();
+            const check = jest.fn().mockReturnValueOnce(false).mockReturnValueOnce(true);
+
+            const promise = retryWithBackoff({
+                check,
+                onSuccess: jest.fn(),
+                initialDelay: 50
+            });
+
+            // Advance timers by 50ms to resolve the default delay (50 * 2^0 = 50ms)
+            jest.advanceTimersByTime(50);
+
+            await promise;
+            expect(check).toHaveBeenCalledTimes(2);
+
+            jest.useRealTimers();
+        });
     });
 
     describe("error propagation", () => {